In Loop, the statement needs to be written only once and the loop will be executed 10 times. An operation is done, such as getting an item of data and changing it, and then some condition is checked such as whether a counter has reached a prescribed number. Counter not Reached: If the counter has not reached the desired number, the next instruction in the sequence returns to the first instruction in the sequence and repeats it. Counter reached: If the condition has been reached, the next instruction “falls through” to the next sequential instruction or branches outside the loop.

There are mainly two types of loops:

1.Entry Controlled loops: In this type of loop, the test condition is tested before entering the loop body. For Loop and While Loop is entry-controlled loops.

2.Exit Controlled Loops: In this type of loop the test condition is tested or evaluated at the end of the loop body. Therefore, the loop body will execute at least once, irrespective of whether the test condition is true or false. the do-while loop is exit controlled loop.

for Loop: A for loop is a repetition control structure that allows us to write a loop that is executed a specific number of times. The loop enables us to perform n number of steps together in one line

While Loop: While studying for loop we have seen that the number of iterations is known beforehand, i.e. the number of times the loop body is needed to be executed is known to us. while loops are used in situations where we do not know the exact number of iterations of the loop beforehand. The loop execution is terminated on the basis of the test conditions. We have already stated that a loop mainly consists of three statements – initialization expression, test expression, and update expression. The syntax of the three loops – For, while, and do while mainly differs in the placement of these three statements.

do-while loop: In do-while loops also the loop execution is terminated on the basis of test conditions. The main difference between a do-while loop and the while loop is in the do-while loop the condition is tested at the end of the loop body, i.e do-while loop is exit controlled whereas the other two loops are entry-controlled loops.